Oleophilic substances, and in particular fat-soluble vitamins such as A, D, E and K, have had limited incorporation into dry materials because of their oil-like nature. Accordingly, oleophilic substances have tended to be macroencapsulated and delivered as units of coated oil. Unfortunately, however, such delivery drastically restricts the applications for which these oleophilic substances are suitable. For example, current commercial techniques can only produce concentrations of vitamin E which range up to 50% by weight.
The present invention overcomes the limitations inherent in the prior art encapsulation techniques and allows for production of high potency vitamins in a free flowing powder form. Such a form allows for delivery into multiple vitamin tablets or foods, such as cereal, and provides the advantages of reducing tablet size or the bulk required for subsequent delivery. Of particular interest is high potency Vitamin E in which Vitamin E forms greater than about 50% by weight of a dry powder or beadlet.
The prior art, as represented by Lim, et al., U.S. Pat. No. 4,389,419, issued Jun. 21, 1983, the contents of which are herein incorporated by reference, describes the formation of an emulsion consisting of a continuous phase aqueous solution of an alkali metal alginate, and optionally, a water-soluble alcohol-insoluble filler such as a polysaccharide, and a dispersed phase of an oleophilic substance. The emulsion thus produced is then formed. into droplets which are emersed into an alcoholic solution of multi-valent cations, to produce a water-insoluble shape-retaining alginate matrix filled with precipitated polysaccharide and enclosing plural oil droplets.
The Lim, et al. approach differs markedly from that of the subject invention in which an oleophilic substance is incorporated into a primary polymer containing solution, and then solidified under mixing conditions to encapsulate the fat-soluble substance and form an encapsulated fat-soluble composition. Through the use of mixing conditions in forming the primary particle, far greater concentrations of oleophilic substances relative to those achieved by Lim, et al. can be realized. As stated by Lim, et al., the amount of oil may range from between 1% up to nearly 30%. However, at the higher end of this range, the stability of the Lim, et al. oil-in-water emulsion is decreased and the quality of the Lim, et al. microcapsule is reduced. Additionally, the Lim, et al. droplets need to be removed from the alcoholic solution and washed, or otherwise treated, to remove any residual alcohol, thus requiring extra production steps.
Another markedly different approach employed for encapsulating vitamin or mineral nutrients, such as thiamine, is described by Hall, et al., U.S. Pat. No. 4,182,778, issued Jan. 8, 1980, the contents of which are herein incorporated by reference. Hall, et al. describes encapsulation by fluidizing the nutrient in a gaseous stream and contacting the nutrient with finely atomized droplets of a coating solution. Nowhere, however, is the application of the Hall, et al. suggested for use with oleophilic substances.
As described below, the concentration of the oleophilic substance in the subject invention typically ranges from about 30% to about 90% based on the dry weight percentage of the final encapsulated oleophilic composition. These percentages are far superior to those described by Lim, et al., and form a major breakthrough over the current state of the art which only allows percentages of vitamin E to reach about 50%. Thus, the subject invention fulfills a long-felt need in the art for a high potency encapsulated oleophilic composition.